The adverse health effects of many metals and radionuclides present in the environment are well recognized. While certain toxic metals and radionuclides are considered to be carcinogens, others can lead to poisoning, DNA damage of blood cells, liver damage and enzyme inactivation in humans. Hence the detection/determination of trace amounts of these metal ions in the environment is critical. Current environmental monitoring methods generally involve on-site collection followed by transportation to a remote testing facility. This proposal aims at developing a fluorescent chemosensor for at source detection of toxic metals and radionuclides. New conjugated polymers with a variety of Lewis base binding sites will be evaluated as potential selective probes for an array of metal ions such as Hg2+, N2+, Pb2+, As2+, Cd2+, Sr2+, Cs2+, Co2+, U6+ and Cr6+. Structural modifications in both the polymer and receptors will be used to improve the selectivity and sensitivity of the probes. Thin film structures on optical substrates will then be prepared either by spin-coating or by self-assembly of the polymers via coordination chemistry to form high surface area molecular architectures on optically transparent substrates. The ultimate goal will be the incorporation of the polymeric materials into fiber optic fluorescent sensors for remote environmental sensing.